| Thin-walled light steel structure as a new steel structure system, has good integrity, high-statically indeterminate, multi-channel seismic line of defense, and in line with our environmental, energy, water, housing industry policy. Soldered directly to the node is used in the type of structural system. Because of the repeated welding node area, the node of the ductility, stiffness and plastic deformation will reduce and plates of the node region will be induced brittle fracture. To this end, the local haunch beam end can effectively improve the flexural capacity, in order to achieve "strong nodes, weak levers" seismic design goal. This way can make the relocation of plastic hinge. In addition paper proposes a new type of beam-column connection. C-shaped steel as longitudinal frame beam is moved and welded the outer surface of the vertical column. Lateral frame beam welding in the C-shaped steel beam can reduce the number of the column tube wall welding and avoid to reduce the bearing capacity of columns because of the column plate burned through.Three types of connection (JD node, GJD node and XJD node) are carried out low cyclic loading test under different axial compression ratio, to explore the failure modes of these nodes, study of the node hysteresis curve, stiffness degradation, ductility, energy dissipation capacity, analysis of strain distribution and changes on the key part. In the three types of nodes, GJD nodes have a better energy dissipation capacity, ductility, and higher the carrying capacity. XJD nodes have a long yield platform, and produce ductile fracture. The cumulative energy dissipation capacity is significantly higher than the two nodes. JD nodes produce brittle fracture. Performance of JD node is relatively weak compared to the two other nodes.By using the nonlinear finite element ANSYS numerical simulation of the GJD node and XJD node under the low cyclic loads, the numerical simulation and experimental results are analyzed to verify the correctness of the finite element results. Based on the finite element results, by changing the geometric parameters of GJD node haunch parts (haunch height, haunch thickness and haunch length) and geometric parameters of XJD node (the thickness of square steel beam and column, the thickness and height of C-shaped steel beam, The relative position of the square steel tube beam and C-shaped steel beam), the impact of these factors on the node mechanical properties are explored. For GJD node, haunch height and haunch thickness have a significant impact on the hysteretic behavior of the node. The impact of the haunch length is relatively small. At the same time failure mode of the node has shifted when the corresponding value is lowered. For XJD node, the changes of the thickness of square steel column, square steel beam, and C-shaped steel beam have a varying degrees impact on the hysteresis curve, carrying capacity and initial stiffness. The height of the C-shaped steel has a significant impact on hysteresis curve. When the height is reduced, the pinching of the hysteresis curve disappears. And the hysteresis curve display a full and strong features of the energy dissip the pinching of the hysteresis curve disappears ation capacity. The relative position of the square steel tube beam and C-shaped steel beam has a significant impact on node performance. Hysteretic curve shape shows spindle, and this method eliminates the node positive and negative bearing capacity difference. |
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